Steam heating method



Feb. 23, 1943. E R 5 2,312,192

' STEAM HEATING METHOD Filed June 17, 1942 3 Sheefcs-Sheet l INVENTOR Jae 732.24 6

NEY

, J; T. READER STEAM HEATING METHOD Feb. 23, 1943.

5 Sheets-Sheet 2 fined Juhe 17, 1942 IN VEN TOR I ATTOR NE) 5 Patented F eb. 23, 1943 Joseph T. Reader, Detroit, Mich., assignorto Syn chronized Systems Company, a partnership composed of Joseph T. Reader, Charles Machris, Harold E. Rose, Albert E. Fisher, and

Robert P. Butler Application June 17, 1942, Serial No: 447,367

17 Claims.

This invention relates to a method of heating buildings by the use of steam and has for its principal object the provision of such method by the practices of which buildings may be heated more evenly and more economically than is possible with existing systems.

Objects of the invention include the provision of a method of heating a building by steam by the practices of which a building may be more evenly heated in all kinds of weather than by methods heretofore practiced; the provision of a method of heating a building by steam by the practices of which the initial cost of equipment may be substantially reduced; the provision of a method of heating a building by steam by the practices of which those radiators more remote from the source of steam may be maintained at their full efficiency regardless of the weather conditions; the provision of a method of heating a building by steam by the practices of which less steam is necessary than in systems operating in accordance with conventional methods, therefore permitting economies to be realized in boiler installations' and the like; the provision of a meth d of heating a building by steam in which the adding of additional heating units to the system will not afiect the theretofore established equilibrium of the system; and the provision of a method of heating a building by steam by the practices of which the certain steam traps of the system are relieved to a'material extent of the load which they must carry in accordance with conventional steam heating practices, thereby increasing the life ofthe traps and aiding in maintaining the system in an eflicient state of operation for a greater length of time than in conventional systems.

Further objects of the invention include the" provision of a method of heating a building by steam including the steps of cyclically admitting steam to the steam side of the system and then equalizing the pressure throughout the steam side of the system; the provision of a method of' heating a building by steam including the alternate steps of admitting steam to the steam side of the system and then closing on" the flow ofsteam to the system and evacuating the return side of the system; the provision of a method of heating buildings by the use of steam including the steps of alternately evacuating the system of nately admitting admitting steam to the steam side of the system and evacuating the'return-side of the system", permittingthe pressures in the steam side of the system to" equaliie while the return side is being evacuated, and permitting the pressures in the return side to equalize while steam is being admitted to said steam sider; the provision of a method of heating buildings .by steam under sub atmosp'heric' pressure including the steps of evacuating the system of air and non-condensable gases at fredunt intervals to maintain the desired degree of vacuum therein and shutting on the now of steam to the system during such evacu ion period; the provision vor a method of h'aiti g buildings by steam under sub-atmospheric pr ssu're in which the" pressure of steam in theradiatorsarid piping 0f the steam side of the system is equalized at rreq en mtervals; the provisioriof a metno'd'df heatingfbuild ings by the use of steam under sub-atmospheric pressure and in which the flow of steam to the system is controlled by a attomaucany operable in response to variations of pressure the system, including the stepof closing the valvethe provision of aimetho'd' of heating buildings" by steam asset-vs described including the step of automatically varying the differential of pre's j"-' sure between the steam side'and the return side of the-system, and consequently thelvo'lume and temperature 'ofthe steam admitted to the sys:

term, in accordance with theheatingideniandsof the system.

The above being" among" the (streets of the present invention the same consists in certain novel steps of-operation inthe controland'op'ration of a steam heating system to behe're'inafte'r' described with reference to the accompanying drawings; and then claimed,- having the above and other objects in view.- 7 v V v 1 In the accompanying drawings which illustr'ate 'steamheating systems capable of being operated in* accordance with the method of; the present invention, and in which like numerals refer 'to like parts throughout-the several differ ent'vi'ews", V

.Eig. .1":is"a more-or less diagrammatic, fragmentary view of 'a steam heating system .illustrating one form of apparatus bymeans of which the method of the present invention-may be carri'ed-out; I

Fig; 2 isan enlargedfragmentary, partially broken; partially sectioned View of :therestriction and at a higher pressure Fig. is an enlarged partially broken, partially sectioned view taken centrally through the control diaphragms for the steam control valve of the construction shown in Fig. 3; and,

Fig. 6 is a side elevational view illustrating a difierent form of apparatus which may be added to the type of steam control valve shown in Fig. 4 to carry out the method of the present invention.

cur when the steam valve is open. Likewise those radiators at the more remote ends of the steam main will quickly establish a difierential of pressure across their opposite ends the same as those closer to the source of heat supply and will thus exert an equal tendency to pull steam from the reservoir thus created when the steam admission valve is closed. All of the disadvantages occurring because of the pressure drop in conventional systems are, therefore, quickly and definitely eliminated once the steam admission valve is closed. In other words, the diiferential of pressure across all radiators is practically equalized.

The present invention is applicable for use in the heating of all types of buildings, whether.

residential or business or otherwise, but will usually be found of greatest importance in the larger types of buildings inasmuch as the heating of large buildings usually offers greater problems than in small buildings.

The present invention relates to the sub-atmospheric type of heating systems. That is a vacuum pump is connected with the return line and is controlled to operate for a sufiicient length of time and at sufficiently frequent intervals to remove the air and non-condensable gases from the system. The condensed steam is removed in the usual manner. The steam is preferably admitted under sub-atmospheric conditions but under some conditions may be admitted at some positive pressure above atmospheric pressure where, as in extremely cold weather, an unusually heavy demand is placed upon the system.

In the practice of the present invention it is recognized that unequal distribution of steam is a natural consequence of the pressure drop due to the flow of steam in any heating system. Such pressure drop does occur in a steam heating system operated in accordance with the present invention whenever steam is admitted to the steam side of the system through the control valve. The system is, however, operated in such a manner as to minimize the effects of such pressure drop. This is accomplished by admitting steam to the system until the degree of vacuum in the return line is reduced, or the positive pressure therein is increased, to a predetermined value upon which the admission of steam to the system is stopped and the return side of the system is evacuated to reduce the absolute pressure, or to increase the degree of vacuum therein to a predetermined desired value. As soon as the ad- 'mission of steam to the system is stopped, the

flow of steam to the system, of course, ceases and the very condition which causes pressure drop is thereby eliminated. As soon as the steam entrance valve closes then there is no beginning or end to the steam main and it becomes merely one long reservoir of steam throughout the entire length of which the steam pressure is quickly equalized and all of the radiators are in the same relative position with respect to this source of steam. In other words, the pressure throughout this entire reservoir is quickly equalized, and in becoming equalized those radiators at that end of the steam line closest to the source of steam than that at the remote end of the system when the valve closes, feed a portion of the steam therein back into the steam main, which effect thus aids in correcting the effects of unequal distribution which tends to oc-' The Vacuum pump being operated under such conditions and the pressure in the return side of the system being practically equal under all conditions, the cumulative effect of air leakage on the more remote radiators is quickly eliminated and .the pressure drop across all radiators being practically the same at such time air, non-condensable gases and condensate are withdrawn from all radiators equally and as such air, noncondensable gases and condensate is removed the steam is naturally expanded and upon condensing in the radiators exerts a pull on the steam remaining in the reservoir thus created so that all radiators are free to pull steam from the reservoir with equal effect. It has been previously mentioned that the effect of steam packing in those radiators closest to the steam admission valve is reduced under such circumstances because of the fact that the pressure in the entire steam side of the system is equalized and, therefore, some of the steam in the leading radiators is withdrawn into the main there to be in a position to supply any radiator requiring it. The pressure across all radiators being practically the same under such conditions, while the steam valve is closed no steam trap is placed under any more stress than any other steam trap in the system and thus the greater leakage and short circuiting of those traps serving the radiators nearest the source of heat supply in conventional systems is eliminated under such conditions. Furthermore, in thus closing the steam admission valve when the vacuum pump is started, the belching of steam into the steam main, which occurs in conventional systems under such circumstances and tends to aggravate unequal distribution, is definitely eliminated.

Furthermore, in accordance with the present invention, during those periods of operation when steam is being admitted to the steam side of the system, the operation of the vacuum pump is discontinued and the discharge end of the return line is sealed from the atmosphere. This causes the pressures in the return line to be equalized throughout under such circumstances, prevents the discharge of live steam leaking past the traps from being discharged from the system at such time and helps to equalize the pressure differences across all the traps under such circumstances.

It will be appreciated that orifices on the inlet to the radiators are a hinderance in practicing the method of the present invention rather than a help because such orifices would tend to interfere with the re-distribution of steam in the steam side of the system from the radiators at the high pressure end thereof to the radiators at the lower pressure end thereof. Consequently the use of orifices in the practice of the present invention are not only unnecessary but are believed to be a disadvantage.

From the above it will be appreciated that in the practice of the present invention a cyclic operation occurs in that steam is first admitted to the system, during which time a pressure drop between different portions of the steam side of the system naturally occurs, and then the supply of steam to the system is discontinued and evacuation of the return side of the system is effected during which time the steam in the steam side of the system is re-distributed so as to equalize its pressure throughout its entire extent, the air and non-condensable gases and condensates being removed at such time, and then after such re-distribution has been accomplished, more steam is admitted to the system. During those periods when steam is being admitted to the system the return line is sealed from the atmosphere and the pressure throughout its length equalized. Operation of the vacuum pump during periods of non-admission of steam is necessary in order to remove the air and non-condensable gases from the radiators in order to condition them to receive the supply of steam which is now expanded and which they are now in condition to draw from the reservoir on an equal footing with all other radiators in the system by reason of having the same pressure drop between their opposite ends. Were it not for the removal of the air, non-condensable gases and condensates from all of the radiators when the supply of steam to the system is discontinued, while some benefits might be realized because of the equalization of pressures on the steam side of the system, the effect would be incomplete and, therefore, not fully satisfactory for the reasons above given. When it is understood that usually such vacuum pumps operate from ten to twenty times an hour it will be appreciated that according to the practices of the present invention the pressures in both the steam side and the return side of the system are individually equalized during the greater proportion of the time of operation of the system and consequently those more remote radiators which in conventional systems are being starved of steam, are in accordance with the present invention supplied amply.

In all of the above discussion it has been assumed that each time the vacuum pump starts up the steam valve is completely closed so as to completely shut off all flow of steam to the system. While such operation is, of course preferable, it will be appreciated that the system will operate to a great advantage as compared to conventional systems even though the flow of steam to the system is not completely shut off when the vacuum pump begins to operate. The important feature is that when the vacuum pump is started the normal flow of steam to the system, instead of being increased as in conventional systems due to belching as previously described, is materiall restricted in its flow if not completely stopped. A relatively small flow of steam not sufficient to create a volume of steam flow which will be materially restricted by friction in flowing through the system will, of course, not create the objectionable conditions in conventional systems previously described. Accordingly, in the following description and claims where it is specified that the steam conbut also one in which the normal flow of steam to the system is materially restricted and, as far as the above described operation of the system is concerned is, therefore, substantially cut oif.

In the broader aspects of the invention it makes no difference what form of means is employed for causing the steam valve to shut and the vacuum pump to initiate its operation at desired intervals. However, in view of the fact that the degree of vacuum in the return line is usually the controlling factor in the operation of the vacuum pump, and the degree of vacuum in the return line usually governs the amount of steam fed to the system, as a matter of convenience it is preferable to employ the initiation of the operation of the vacuum pump, or some effect produced thereby, to control the closing of the steam valve. Where the steam valve i normally controlled by the diiferential of pressures existing in the steam main and in the return line as through a diaphragm subjected to the pressure of the steam main on one side and the pressure in the return line on the opposite side, then if that side of the diaphragm subjected to the pressure of the return side of the system is connected directly into the vacuum receiver and there is a suiiicient resistance to flow between the return line proper and the receiver, as soon as the vacuum pump begins to operate the reduced pressure in the receiver acting on the one side of the diaphragm will cause the steam control valve to close. On the other hand an aditional diaphragm may be connected to the valve and subjected to the reduction in pressure in the vacuum receiver due to operation of the vacuum pump toeffect the desired result, Furthermore, a suitable electricallyactuated device, such as a solenoid, magnet, motor or the like, either acting directly or serving to control a fluid pressure motor of any suitable type, may be connected parallel with the circuit for energizing the electric motor which drives the vacuum pump, and thus be automatically actuated to close the steam admission valve whenever the vacuum pump "motor is energized. Illustrative embodiments of preferred apparatus capable of producing "the desired result are shown in. the accompanying drawings by way of illustration.

Referring now to the accompanying drawings and particularly to Fig. 1 in which a typical embodiment of a steam heating system operated in accordance with the method of the present'invention is disclosed, the numeral ill indicatesgenerally a suitable steam boiler of any approved type which discharges steam therefrom into a steam main l2. A shut-off valve 14 is shown in the main I2 adjacent the boiler It so as'to enable the system to be completely cut off from the boiler Where desirable or necessary as, for instance, in the case of repairs'to the system. Various branches it, each provided with a shut-off valve [8 lead off from the main [2 and each branch I 6 is provided with additional branches 20 to each of which one or more heat diffusing media, which may be of any suitable or conventional type, but for the purpose of simplicity of description in the drawings they are here shown as radiators 22, are connected'by means of pipes 24. The term radiator when used in the :specification and claims is to be interpreted to mean any suitable or conventional heat diffusing media or apparatus. The outlet sides of the radiators 22 are connected bypipes 26 to a vacuum return line 28, a thermostatic trap 39 being provided in each of the pipes 26 at the outlet side of each "radiator in accordance with conventional :practice. The lower ends of the branches 20, which.

extend below the corresponding radiators 22, as well as other low points in the system, are also connected to the vacuum return line 28 by means of pipes 32 in which some suitable type of sealing means are preferably located. Such sealing means may take any usual or desirable form such as a water leg, trap or the like but for the purpose of illustration are shown as traps 34.

The vacuum return line 28 discharges into a receiver 40 in which the condensed steam is separated from the non-condensable gases and vapors, such condensed steam beingdrawn out of the receiver and returned to the boiler by means of a pump 42 and pipe line 44 in which a check valve 45 is located, the pump 42 being driven by a motor 45 of a float controlled type conventionally employed in the art for this purpose. The receiver 40 is connected by a pipe line 48 with a vacuum pump 50 which discharges into a separator 52. The pump as may be driven in any suitable manner as, for instance, by a steam or other engine, steam turbine, electric motor or the like, an electric motor 54 being shown by way of illustration. The discharge from the separator is through a check valve 55 which operates to seal the return line 28 from the atmosphere whenever the vacuum pump 50 is not operating.

Operation of the motor 54 effects operation of the vacuum pump 58 which in turn places the interior of the receiver 4i! and consequently the vacuum return line 28 under a partial vacuum, the condensed steam flowing into the receiver from the vacuum line 28 being separated out in the receiver and returned to the boiler in accordv ance with conventional practice.

The vacuum pump t may be controlled in any suitable way to effect intermittent operation thereof. In other words, suitable time controlled mechanism may be provided for energizing the motor 54 for desired periods of time at definite intervals of time. On the other hand, the motor 54 and consequently the pump 50 may be automatically controlled in accordance with the demands of the systemas based on outside temperatures. For instance, a plurality of commercial type thermostats located so that they will be affected by outside temperatures, may be connected to a suitable vacuum operated regulator for the motor 54, and each thermostat adjusted so that its corresponding regulator will make contact at different temperatures than the rest, the corresponding regulator serving to effect operation of the motor 54 whenever the vacuum in the system drops a predetermined amount below the value of the desired maximum in the system to thus intermittently increase the vacuum in the system to the desired value commensurate with the heating requirements based on the then ex sting outside temperature.

A simpler method, although not automatic, is ,-shown in the drawings by way of illustration and comprises a control panel 55 provided with a movable control arm 58 mounted thereon movable to any one of a plurality of different positions indicated by the buttons 60. All except one of the buttons 6!! may be associated with a conventional type of pressure operated switch device each of which has a conventional type of pressure responsive element (not shown) associated therewith and connected by means of a pipe fi tto the vacuum return line 28, so that when the motor 54 is controlled through any one of the switches associated with these latter buttons it will automatically cause operation of the motor 54 to maintain the suction pressure in the vacuum return line 28 between predetermined limits. As a matter of illustration it may be assumed that when the control arm is moved into alignment with righthand button 60 so as to select the corresponding pressure operated switch, the motor 54 will be controlled to reduce the vacuum in the return line 28 to a suction pressure of twenty inches of mercury, that when such suction pressure is attained in the vacuum return line 28 the operation of the motor 54 will be discontinued, and that when the suction pressure in the return line drops to eighteen inches of mercury the righthand switch will automatically re-close and again bring the suction pressure in the system down to twenty inches of mercury, this cycle being repeated as long as the control arm 58 is in alignment with or engaged with the righthand button 60. When the control arm 58 is turned to the button 60 next to the righthand button above described it may be assumed, for instance, that the pressure operated switch associated therewith will effect operation of the motor 54 to reduce the suction pressure in the return line 28 to fifteen inches of mercury, will shut off the motor 54 when this value is reached and will again cause operation of the motor 54 when the suction pressure in the return line 28 has been reduced to thirteen inches of mercury. Likewise the remaining buttons thus associated with the pressure responsive switches may be adjusted so that when the control arm 58 is aligned with them it will cause the suction pressure in the return line 28 to be reduced to values varying in steps of, for instance, five inches of mercury from those already described. One of the buttons 60, assumed to be the lefthand button 63 illustrated, preferably has no pressure responsive switch associated therewith so that when the arm 58 is turned to it the motor 54 will be caused to run continuously regardless of the suction pressure in the return line 28. This arrangement is desirable for use in starting up a cold system.

In order to variably control the flow of steam into the main l2 from the boiler It a pressure reducing control or steam admission valve indicated generally at 10 is interposed in the main [2 adjacent to the valve l4 but on the down stream side thereof. While any suitable type of pressure reducing valve may be employed for this purpose, one conventional type of valve is shown in Fig. l, and in detail in Fig. 4, by way of illustration and, referring particularly to such latter figure, it will be noted that it comprises a casing or housing having an inlet 52 and an outlet 14, together with a pair of ports E5 connecting the inlet and outlet. The ports 15 are each formed to provide a valve seat at their upper edges with each of which a valve 18 is arranged in cooperative relationship. The valves 18 are rigidly connected together by means of a post 80, the construction thus providing a balanced valve of a conventional type familiar to those skilled in the art.

In order to operate this valve 10 the valves I8 are controlled in their movement by a pressure responsive device subject to variations of pressure in the system. To this end, the lower face of the valve 10 is closed by a cap 82 carrying a post 84 to the lower end of which is fixed a two-part housing 86 centrally divided by a flexible diaphragm 88 Sealed at its margins thereto and forming chambers 90 and 92 interiorly of the casing 88. A stem 94 fixed concentrically at one end to the valve assembly, including the valves "I8 and post extends downwardly through the post 84 and into the'casing 86 where it is fixed to the center of the diaphragm 88, a suitable packing indicated generally at 96 serving to seal the stem 94 in its passage through the post 84. This assembly may be loaded toward open or closed valve condition in any suitable or conventional manner as, for instance, by springs, weights, or the like. Weights are shown by way of illustration and arranged in a conventional manner. To accomplish this, the lower face of the casing 86 is provided with a boss 98 thereon in which the stem 96 is also suitably sealed and the boss 98 is provided with an offset fixed arm II!!! to which one end of a link I92 is pivotally connected. The opposite end of the link I02 is pivotally connected to a bar I64 to which the lower end of the stem 94 is also pivotally connected as at I06. On the opposite side of the pivot I06 from the link I02 the boss 98 is provided with a rigid bifurcated arm I08 within which the bar I04 is guided for vertical movement. The bar I94 has a plurality of weights adjustably mounted thereon longitudinally thereof, the weights IIil ordinarily remaining fixed once the system is adjusted, and the weight H2 is readily adjusted along the length of the bar I04 and is normally the only one employed in adjusting the load on the valve during normal operation. Although the weights may be adjusted to urge the valve to either closed or open position, the arrangement of the weightsshown normally urges the valve I8 toward open position.

In carrying out the method of the present invention the chamber 90 in the casing 85 is connected by means of a pipe I28 with the steam main I2 on the down stream side of the valve I9, and the chamber 92 is connected by a pipe I29 with the vacuum receiver 40 on the down stream side of the suction strainer I30 conventionally employed therein. The purpose of so connecting the line I29 into the vacuum receiver 40 is so that when the vacuum pump 50 starts up the chamber 92 on the under-side of the diaphragm 88 will be subjected to a greater degree of vacuum than exists in the return line 28. Ordinarily the suction strainer I 30 will offer a suificient resistance to the flow of air and non-condensable gases from the return line 23 into the receiver 40 to effect this purpose, particularly where a desirably large vacuum pump b is employed, but where the resistance of the suction strainer I30 is not sufficient for the purposes hereinafter described then a further restriction may be inserted in the return line 28 or in its connection to the receiver 40 to effect the desired-result. As a matter of illustration such restriction is indicated within the circle 2 in Fig. l and shown in detail in Fig. 2 from which it will be apparent that the return line 28 is broken at this point and provided with a pair of coupling flanges ISI between which is clamped an orifice member I32 having an orifice I33 therein of materially smaller cross-sectional area than the cross-section-a1 area on the return pipe 28. It will be understood that the restriction shown in detail in Fig. 2 may or may not be necessary depending upon the conditions above stated.

A tank 34 is preferably interposed in the line I23 and this tank becomes filled with condensed steam and provides a constant head of water on the upper side of the diaphragm 38 so as to eliminate possible variations in. control of the valve "III due to variations in the amount of condensed steam which might otherwise act thereon.

The restriction afforded by the suction strainer I30 or by the orifice plat-e I32, or both, is such that when the vacuum pump 50 is not operating the degree of vacuum in the receiver 40 will be identical to that in the return line 28. Consequently when steam is being admitted to the system through the valve If! the amount of such steam will be governed by the diiference in pressure between th entrance end of the steam main I2 and the return line 28, the valve I0 thus being controlled as a simple difierential pressure operated valve tending to maintain a constant differ-- ential of pressure between the two sides of the system. However, due to the manner of connecting the line I29 into the vacuum receiver 40 on the down stream side of the restriction afforded by the suction screen I39 or the orifice plate I32- if the latter is employed in conjunction therewith, as soon as the vacuum pump 59 starts to operate the vacuum will increase in the receiver 40 at a faster rate than it will in the return line 28 and, consequently, the lower face of the diaphragm 88 will be subjected to a greater vacuum than simultaneously exists in the return line 23. In accordance with the present invention the restriction offered by the suction screen I30 or by the orifice I32, or both where both are employed is such that under such conditions the reduction of vacuum in the receiver 40 is suificient to cause the diaphragm 88 to close the valve III, or to substantially oloseit, thereby completely or substantially cutting off further fiow of steam into the steam main I2 from the valve I3. As previously explained under such conditions the pressure in the steam sideof the system including the main I2 on the down stream side of the valve III, the branche I6, 2i! and radiators 22 is'almost-immediately equalized through the entire system. As previously explained this fact, tog-ether with the fact that the vacuum pump is operating under such conditions and withdrawing the air' and non-condensable gases and condensates from the radiators 22; any excess steam that has been packed into those radiators closest to the valves I0 is returnedto the main and branches and the steam in' the main and branches on the down stream side'of the valve It thereafter serves as a reservoir of steam from which all of the radiators, including those at the remote end of the line, may draw from equally as the steam in them condenses, to re plenish the steam condensed therein and to replace the air and gases withdrawn therefrom. The steam in the main I2 and branches It and 20 will, of course; continue to expand under such conditions as the air and non-condensable gases are withdrawn from the radiators and as the steam in the radiators is condensed but neverthe less will provide a reservoir of steam to be drawn from-during the interval that the vacuum pump is running. Even though the steam valve 10 may not be completely closed, as long as it is closed sufficiently to eliminate a'pressure difference 'sufi'lcient to give rise to the objectionable features previously discussed, the purposes of the present invention will still be carried out to a major extent.

It will likewise be understood that'when the desired high limit of vacuum has been reached in the return line and the vacuum pump 50 stops operating, the check valve 55 will close and the steam valve HI will open. Steam will thus be admitted to the steam side of the system while the pressures throughout the length of thereturn side of the system will be equalized. Thus the system will operate to alternately equalize the pressures on the steam side and the return side, with all of the attendant advantages previously described.

In the construction above described, employing the valve shown in Fig. 1 and in detail in Fig. 4, because the valve is provided with a simple dilferential pressure control, the same differential of pressure will be maintained between the steam side and the return side of the system when the valve I is operating to control the flow of steam into the system during those periods that the vacuum pump 50 is not operating regardless of the degree of vacuum maintained in the system. In systems of this type variation in heat output of the system to meet conditions of outside temperatures is, of course, controlled by varying the amount of steam fed to the system and such amount of steam is in turn varied by varying the pressures under which the system operates. For instance, in mild weather when a relatively small amount of heat is required, the system is operated under a high degree of vacuum as in such case one unit of steam, for instance one pound, will occupy a much greater volume than when under a higher absolute pressure and will have a lesser temperature. Thus the lower temperature steam in occupying such large volume gives 01f less heat per unit of volume of theradiators than would be the case if it occupied a smaller space under a higher absolute pressure and higher resultant temperature; When the outside temperature drops and a greater heating effect is required of the heating system, then the degree of vacuum maintained in the system is reduced, in other words the absolute pressure is increased, with the result that one unit of higher temperature steam occupies a smaller volume and, accordingly, gives off a greater amount of heat per unit of volume of the radiators. It is in order to obtain this control of the heating e'lfect of the system that the control including the arm 58 and contacts 60 previously described is provided in the illustrative embodiment shown.

However, for the purpose of relieving the stress on the traps in the system and for other reasons it is desirable to employ no more differential of pressure between the steam side and the return side of the system than is necessary to effect the proper operation of the system. Accordingly, when the system is operating under a high degree of vacuum and the steam in the steam side is of small quantity and highly expanded and, therefore, offers less friction to flow through the system, a smaller differential of pressure can be employed than where the system is operating under a'low degree of vacuum and the steam in the steam side is, therefore, greater in quantity and denser and the system offers a greater amount of resistance to its flow through the system. In fact where the temperature is extremely low outside of the building and even though the system may be of the so-called sub-atmospheric type. the steam entering the main I2 through the valve may, under some conditions, be under a positive pressure in order to obtain the desired heating efiect from the system. Under such conditions the differential of pressure between the entrance end of the steam main and the return line will, of course, be required to be relatively great in order to insure steam being distributed to the more remote radiators.

The requirement of a relatively large differential of pressure between the steam side and the return side of the system under the conditions above described is particularly necessary in steam heating systems of conventional construction and while, by the practices of the present invention, the requirement of such great differential is materially reduced, nevertheless it may be desirable under some conditions to recognize the requirement of varying differential of pressures between the steam side and return side of the system and to make provisions for establishing the same.

Where the valve employed in the construction illustrated in Figs. 1 and 4 is employed, the differential of pressure between the steam side and the return side of the system may be regulated whenever the degree of vacuum under which the system is operating is varied, by shifting the weight I I2 on the rod I04 to vary the load on the valve 10. While any competent engineer familiar with these systems is quite capable of shifting the weight I I2 to vary the differential maintained between the steam and the return sides of such system to correspond with the minimum capable of being used under a particular condition of operation, it has been found that in actual practice the tendency of most of the engineers in charge of such systems is to set the weight H2 to provide the differential of pressure required under the most severe heating conditions and to allow it to remain in such position regardless of how mild the weather may become.

The pressure differential between the steam side and the return side of the system may be automatically varied to correspond with the degree of vacuum under which the system is oper-v ating to correspond with any heating requirements of the system by modifying the valve structure illustrated in Fig. 4 in the manner illustrated in Figs. 3 and 5. The construction illustrated in Fig. 3 is identical to that illustrated in Fig. 1 and except for the modified control for the valve Ill illustrated in Fig. 5, and the modification in the method of connecting the control for the valve into the system illustrated in Fig. 3. Accordingly, those parts illustrated in Fig. 3 which are identical to those illustrated in Fig. 1 are illustrated by the same numerals and a description of the control shown in Fig. 5 and the manner of connecting it into the system will, therefore, serve to describe the entire system shown in Fig. 3.

Referring now to Fig. 5 it will be noted that the upper casing portion 86 and diaphragm 88 is identical to that shown in Fig. 4 and is mounted on and secured to the valve III in identically the same manner. In other words, the upper portion of the construction shown in Fig. 5 is identical to the lower portion of Fig. 4. Additionally, however, in Fig. 5 the lower half of the casing 86 is provided with a plurality of legs or posts II4 fixed thereto and projecting downwardly therefrom and at their lower ends the legs or posts I I4 are rigidly interconnected to the upper half of the second two-part casing IIB interiorly divided by a flexible diaphragm I I8 sealed thereto into an upper chamber I20 and a lower chamber I22. A rod I 24 is centrally fixed to the diaphragm H8 and projects upwardly through the casing I I6 and at its upper end is suitably connected to the rod 94 for equal movement therewith as, for instance, by means of the same pivot pin I06 which serves to secure the rod 94 to the bar I04. The chamber I20 is vented to the atmosphere by means of one or more openings I26 through the upper wall of the casing H6,

In the case where the. valve shown in Fig. is employed and as illustrated in Fig. 3, the pipe I28 connecting with the upper chamber 90 in the upper casing 86 is connected into the steam side of the system in identically the same manner as in the construction shown in Fig. l and previously described. The tube I29, however, instead of being connected into the receiver 49 as in the construction illustrated in Fig. 1, is connected into the return line 28 ahead of the receiver as indicated in Fig. 3 and a tank I34 is connected into such line in the same manner and for the same purpose as the tank I34 is connected into the line I28. Thus the lower side of the diaphragm 88 in the construction illustrated in Fig. 3 is subjected at all times to identically the same pressure as exists in the return line 28 and not the reduced pressure in the receiver 40 as in the construction illustrated in Fig. 1.

In the construction illustrated in Fig. 3 the upper side of the diaphragm H8 is, of course, subjected to atmospheric pressure through the vent holes I26. The chamber I22 between the diaphragm H8 and the lower face of the casing H6 is connected by a pipe I36 directly into the receiver 48 on the downstream side of the strainer screen I therein but no restriction such as the orifice plate I 32, employed in the construction illustrated in Figs. 1 and 2, is shown employed in this construction as it will usually be unnecessary here. In other words, the resistance of the suction screen 30 coupled with the added suction applied to the valve I0 tending to close it has been found sufiicient in most cases to close the valve l8 each time the vacuum pump 5!) is started in operation. Thus from the standpoint of closing the valve IQ each time the vacuum pump 50 starts in operation, the construction illustrated in Figs. 3 and 5 functions in identically the same manner as the first described construction.

The main difierence between the construction illustrated in Figsrl and 3 is as previously described the fact that the control mechanism illustrated in Fig. 5 for the valve 'Hl operates to automatically vary the differential in pressure between the steam side and the return line of the system with variations in sub-atmospheric pressure in the return line as controlled by the vacuum pump 5!) through the control panel 56. In this respect it will be appreciated and as previously explained, when the vacuum pump 5B is not operating the pressures acting on opposite sides of the diaphragm 88 tend to control the valves I8 in the valve 70 to maintain a constant and predetermined difference in pressure between the steam main and the return line. By adding the eifect of the diaphragm H8 to the efiect of the diaphragm 88 and, maintaining a constant pressure on the upper side of the diaphragm I I8, namely atmospheric, as the absolute pressure in the return line is lowered, that is the degree of vacuum is increased, the effect of the vacuum in the return line on the diaphragms 88 and H3 increases at a greater rate than the increased pull of the vacuum in the steam main on the upper side of the diaphragm 88. A variable is thus introduced into the control of the valve I0 which is proportionate to the variations in pressure in the return line 28, so that when the control for the system is adjusted to maintain the system under a relatively high degree of vacuum the differential of pressure between the steam main and the return line as controlled by the valve I0 is automatically reduced, and as the control for the system is adjusted to maintain a lower degree of vacuum in the return line .28 the valve 70 is automatically adjusted to maintain a greater differential in pressure between the steam side and the return side of the system. Thus means are provided for automatically varying the differential of pressure between the steam side and the return side of the system to correspond with variations in the density and quantity of the steam employed in adjusting this system to accommodate its heating requirements in accordance with outside temperatures. The valve iii in Fig. 3 is, of course, operative in the manner described only during those periods of operation when the vacuum pump is inoperative, as otherwise the valve 10 is closed or substantially closed as previously explained.

It will, of course, be appreciated by those skilled in the art that in the broader sense'the application is not limited to the employment of the reduction in pressure in the system through operation of the vacuum pump 50 to efiect closing of the valve 7!) whenever the vacuum pump 5!] begins to operate. Any suitable means acting in synchronism with the operation of the vacuum pump 50 and acting on the valve '50 to close it may, of course, be utilized to effect the desired result. tuated control device connected in parallel with the motor as for the vacuum pump 50 may be employed for this purpose. In such case the electrically actuated control device may act directly or may serve to control the application of suitable fiuid pressure to the valve ID to enforce its closure during operation of the vacuum pump 5%]. As a matter of illustration in Fig. 6 an electrically operated device is shown connected to the valve for eifecting the above described result..

Referring to Fig. 6 it will be noted that the same control mechanism for the valve H1 is employed as in Fig. 4. A bracket I59 is pivotally connected to the stem 54 of the valve through the same pivotal connection lee which serves to connect the stem to the bar use. A chain I52 is connected to the lower end of the bracket I50 and has a coil tension spring I554 interposed in the length thereof. A conventional damper control motor I56 is mounted below and preferablyin line with the stem 94 of the diaphragm control for the valve it and is connected in parallel with the electric motor 54 which drives the vacuum pump 5%) so that each time the motor 54 is energized to operate the vacuum pump 553 the damper control .i58' is also energized. The control I55 is provided with an operating arm I56 which, as is conventional in the case with this type of control, swings angularly about the axis of its drive shaft I68 through a part of a revoluticn when the control is energized, and when die-energized swings around to its original position. The arm 558 is illustrated in Fig. 5 in its inoperative position, that is the position which it assumes when the control IE6 is not energized. The lower end of the chain I52 is connected to the free outer end of the arm I56. When the motor 54 and, therefore, the control I56 is not energized, the chain ifiZ has a sufficient amount of slack in it so as not to offer any interference in the normal operation of the valve l5! and under such circumstances the valve iii operates in a normal manner. However, when the motor 5 1 is energized to start the vacuum pump as into operation, then the arm I58 swings downwardly, tightening the chain I 52 and forcefully closing the valve it and maintains it For instance, any electrically acin closed position during the entire period that the motor 54 is running. The spring I54 is capable of yielding under such conditions to prevent stalling of the damper motor I55 as will be readily appreciated by those skilled in the art. As soon as the degree of vacuum in the return line 28 has reached that point at which the motor 54 is de-energized, the vacuum pump 59 will, of course, stop operating and the arm I58 will return to its inoperative position illustrated in Fig. 6 and thereby free the valve ID for normal operation until the vacuum pump is again started. It will be appreciated that with this construction the pipes I28 and I29 connecting into the chambers 90 and 92, respectively, may be connected into the system either in the manner illustrated in Fig. l or in the manner illustrated in Fig. 3, the latter being sufficient when the control 156 is thus employed.

From the above it will be appreciated that various forms of control mechanism may be employed with a sub-atmospheric type of steam heating system to cause it to operate in accordance with the method of the present invention and that in its broadest aspects the invention consists in so operating the system that steam is admitted to the steam side of the system during one cycle of operation while the return side of the system is sealed from the atmosphere and the pressures therein equalized throughout, and that during the ensuing cycle of operation the vacuum pump is operated to purge the return line of air and non-condensable gases and condensates and the entrance of steam to the system is stopped or substantially stopped so as to give the steam in the steam side at such time an opportunity to completely equalize throughoutthe entire steam side of the system, thereby to effect a re-distribution of the steam contained in the steam side at the time the steam valve is closed and thereby equalize the heating effect of the steam throughout the entire system. The continuous repetition of such cycles causes the system to operate in a more satisfactory, more efficient and more eco nomical manner than any similar type of system heretofore proposed.

Having thus described my invention, what I claim by Letters Patent is:

What is claimed is:

1. In the operation of a heating system including a steam main, a return line and heat diffusing media interconnected therebetween, the steps of withdrawing air and non-condensable gases from said return line during spaced time intervals only and admitting substantial amounts of steam to said steam main only between said intervals.

2. In the operation of a steam heating system including a steam line, a return line, heat diffusing media interconnected therebetween, and a source of steam for said steam line, the steps of intermittently withdrawing air and non-condensable gases from said return line, substantially closing ofi the flow of steam from said source to said steam line during said withdrawal, and feeding steam from said source to said steam line between said periods of withdrawal.

3. In the operation of a heating system including a steam supply line, a return line, heat diffusing media interconnected therebetween, and a source of steam for said supply line, the steps of alternately shutting off the supply of steam from said source to said steam line while simultaneously removing air and non-condensable gases from said return line, and admitting steam fromsaid source to said steam line without withdrawing air and non-condensable gases from said return line.

4. In the operation of a heating system including a steam supply line, a return line and a heat difiusing media interconnected therebetween, the steps of closing said steam line to the admission of steam thereto and removing air and non-condensable gases from said return line, discontinuing the removal of said air and non-condensable gases from said return line and admitting steam to said steam line, and then repeating said cycle of operations.

5. In the operation of a steam heating system, the steps of intermittently evacuating said system of air and non-condensable gases to maintain the discharge side of said system within predetermined limits of pressure, and admitting steam to said system between said periods of evacuation only and in accordance with differences of pressure existing in different parts of said system.

6. In the operation of a steam heating system including a steam line system, a return line system and a radiator interconnected therebetween, the steps of intermittently removing air and non-condensable gases from said return line system and substantially preventing the admission of steam to said steam line system during such periods of removal, and between such periods of removal admitting steam to said steam line system in accordance with the differences in pressure existing between said steam line system and said return line system.

'7. In the cyclic operation of a steam heating system including a steam line, a return line and heat diffusing media interconnected therebetween, the steps of admitting substantial amounts of steam to the steam line during one cycle of operation, discontinuing the flow of substantial amounts of steam to said steam line and simultaneously withdrawing air and non-condensable gases from the return line during the next succeeding cycle of operation, then discontinuing the withdrawal of air and non-condensable gases from the return line while again admitting substantial amounts of steam to the steam line during the next succeeding cycle of operation, and repeating said cycles of operation at frequent intervals.

8. In the operation of a steam heating system including a steam supply line, a return line and a plurality of heat diffusing media interconnected therebetween, the steps of periodically equalizing the pressure throughout the full length of said steam supply line, closing said steam line to the admission of steam thereto during said periods of equalization of pressure therein and supplying steam to said media from that confined in said supply line during such periods, and admitting steam to said steam supply line between said periods of equalization of pressure only.

9. In the operation of a steam heating system including a steam supply line, a return line and a heat diffusing media interconnected therebetween, the steps of intermittently removing air and non-condensable gases from said system and closing the steam line to the admission of steam thereto while equalizing the pressure throughout the entire length of said steam supply line, and admitting steam to the system only between said periods of pressure equalization and in accordance with difierences in pressure existing in different parts of said system.

10. In the operation of a steam heating system including a steam supply line having a differential pressure operated valve controlling the admission of steam thereto, a return line, a heat diffusing media connected therebetween and a vacuum producing means including a receiver, the steps of intermittently subjecting said return line and receiver to the evacuating effects of said vacuum producing means to remove air and noncondensable gases therefrom and simultaneously subjecting said valve to the differences in pressure existing solely between said receiver and said supply line, and during those periods intervening between said periods of evacuation of said return line subjecting said valve to the difference in pressure existing between said steam line and said return line.

11. In the operation of a steam heating system including a steam supply line having a differential pressure operated valve controlling the admission of steam thereto, a return line, a heat diffusing media connected therebetween and a receiver into which said return line is connected through a flow restricting device, the steps of intermittently subjecting said return line to the evacuating effects of a vacuum producing means applied to said receiver to remove air and non-condensable gases therefrom and simultaneously subjecting said valve to the difierences in pressure existing solely between said receiver and said supply line whereby to close said valve to the flow of steam to said steam line, and during those periods intervening between said periods of evacuation of said return line subjecting said valve to the differences in pressure existing between said steam main and said return line, whereby to control the admission of steam to said supply line by differences in pressure existin in said system of which differences the difference in pressure between said receiver and said return line during operation of said vacuum producing means is a material factor.

12. In the operation of a steam heating system including a steam supply line, a return line, and a plurality of heat diffusing media interconnected therebetween, the steps of alternately shutting. off the supply of steam to said steam supply line and removing air and non-condensable gases from said return line, and during the intervening periods admitting steam to said system in accordance with the diiferences in pressure existing between said steam line on the one hand and said return line on the other hand, and automatically reducing amounts of steam admitted to said steam supply line as the absolute pressure in said system is reduced.

13. In the operation of a steam heating system including a steam supply line, a pressure operated valve for controlling the supply of steam to said line, a return line, a vacuum pump connected to said return line through a receiver having a flow restriction between it and said return line, and a plurality of heat diffusing media interconnecting said steam line and said return line, the steps of intermittentl actuating said vacuum pump to maintain said return line between predetermined limits of sub-atmospheric pressure applying the diiference in pressures existing between said steam line and said receiver to said valve to close said valve during operation of said vacuum pump, and

applying the differences in pressure existing between said steam line on the one hand and said return line on the other hand during periods of inoperation of said vacuum pump only whereby to control the admission of heat to said system in accordance with said diiferences in pressures.

14. In the operation of a steam heating system including a steam line, a pressure operated valve for controlling the supply of steam to said line, a return line, a vacuum pumpconnected to the return line, and a plurality of heat diffusing media: interconnecting said steam line and said return line, the steps of intermittently actuating said vacuum pump to maintain said return line between predetermined limits of sub-atmospheric pressure, closing said valve to the admission of steam to said supply line during actuation of said vacuum pump, applying the difference in pressures existing between said steam line and said return line to said valve to control the flow of steam therethrough durin periods: of inoperation of said vacuum pump, and proportionately increasing the effects of the pressure in the return line on said valve over the efiects of the pressure in the steam line thereon as the absolute pressures in said system are reduced.

15. The method of operating a steam heating system having a steam line, a vacuum return line, and a heat difiusing media connected therebetween, comprising the steps of alternately admitting steam to said steam line and removing air and non-condensable gases and condensate from said return line, sealing said return line from the atmosphere whilesteam is admitted to said steam line and sealing said steam line against the entrance of steam thereto while said air and noncondensable gases and condensate ar bein removed from said return line.

16. In the operation of a steam heating system including a steam line, a return line, heat diffusin media interconnected therebetween, and a source of steam for said steam line, the steps of intermittently withdrawing air and non-condensable gases from said return line, substantially closing off the flow of steam from said source to said steam line during said withdrawal, feeding steam from said source to said steam line between said periods of withdrawal, equalizing the pressures throughout said steam line and heat diffusing media during said periods of withdrawal, and equalizing the pressures throughout said return line during feeding of steam to said steam line.

17. In the operation of a steam heating system including a steam line, a return line, heat diffusing media interconnected therebetween, and a source of steam for said steam line, the steps of intermittently withdrawing air and non-condensable gases from said return line, substantially closing off the flow of steam from said source to said steam line during said withdrawal, feeding steam from said source to said steam line between said periods of withdrawal, reducing and equalizing the pressures throughout said steam line and heat diffusing media during said periods of withdrawal, and equalizing the pressures throughout said return line during feeding of steam to said steam line.

JOSEPH T. RELADER. 

